So I am working on plans, so that I can be ready to build a root storage building in the spring. On our land the water table is very near the surface so a true cellar (below ground) is not an option. I'm thinking I will build a shed inside a shed with about 12 inches between the inner and outer wall. Then insulate the space between. If I berm the walls about halfway up combined with the good insulation I should need only minimal heat to keep the inside from freezing in the winter.
Any thoughts on what I should put between the inner and outer walls. I'm trying to minimize cost, so I don't really want to purchase that much insulation. I'm thinking perhaps, scrape styrofoam, or cardboard or shredded paper or wood chips. The challenge with anything organic is keeping it dry so it won't rot.
Pictures to follow, once the snow melts in the spring.